Correlation Coefficient Calculator

Measure how strongly two variables move together.

Separate with commas, spaces or new lines.
Same number of values, in the same order.
Decimals and negative numbers work.
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Result
Correlation r
R²
Regression line
P-value for r
Pairs
Work

Saved Calculations

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Correlation and Regression Formulas

r = Σ(x − x̄)(y − ȳ) ÷ √(Σ(x − x̄)² × Σ(y − ȳ)²)
Slope b = Σ(x − x̄)(y − ȳ) ÷ Σ(x − x̄)²   Intercept a = ȳ − b x̄
Test of r: t = r√((n − 2) ÷ (1 − r²)), df = n − 2

Worked Example

Tips

Correlation isn’t causation, and r only measures straight-line relationships. Check the scatter plot for curves and outliers. Matches Excel’s CORREL, SLOPE, INTERCEPT and RSQ.